Objectives: The aim of the present study was to investigate the relationship between important metabolic risk factors for coronary heart disease (CHD) and type 2 diabetes in shift workers and day workers.
Methods: Cross-sectional data from a sub-population in the WOLF study consisting of 665 day workers and 659 three-shift workers in two plants were analysed.
Results: A higher proportion of shift workers than day workers had high triglyceride levels (> or =1.7 mmol/l), low levels of HDL-cholesterol (<0.9 mmol/l) and abdominal obesity (waist/hip ratio>0.9). The risk of low HDL-cholesterol was doubled in shift workers, (odds ratio (OR): 2.02, 95% confidence interval (95% CI): 1.24-3.28) after being adjusted for age, socio-economic factors, physical activity, current smoking, social support and job strain. High levels of triglycerides were also significantly associated with shift work (OR: 1.40, 95% CI: 1.08-1.83). The OR for abdominal obesity was 1.19, (95% CI: 0.92-1.56). The prevalence of hyperglycaemia (serum glucose > or =7.0 mmol/l) was similar in day and shift workers. No significant interaction was seen between shift work and abdominal obesity with regard to the associations with triglycerides and HDL-cholesterol.
Conclusions: We found a significant association between shift work and lipid disturbances (i.e. low HDL-cholesterol and high triglyceride levels). We did not find any association with hyperglycaemia.